Flat racing's dual Oaks winner Enable will line up in Saturday's high-summer showpiece, the King George VI and Queen Elizabeth Stakes at Ascot (15:35 BST).
Enable is favourite ahead of last year's winner Highland Reel.
The three-year-old will face a host of older horses in one of the principal clashes of the season between the Classic generation and its elders.
As well as Highland Reel and Gosden's Jack Hobbs, both aged five, the four-year-olds Idaho and Ulysses, the recent Eclipse Stakes winner, are all due to take part.
Teddy Grimthorpe, racing manager for Enable's owner Prince Khalid Abdullah, told BBC Sport: "Enable had a little blow [on the gallops] on Tuesday, and everyone was happy."
Dettori, writing in his column for bookmaker Ladbrokes, said he was "really excited" to be back with Enable.
The jockey - who missed Royal Ascot in June following a shoulder injury, added: "She was the reason I came back from injury so early. She really is special. I pushed myself so I could ride her in Ireland and it was worth it."